Tattoos scrambling Apple Watch sensors


Apple confirms dark ink can prevent new wearable from detecting heart rate

Apple has said that some functions on the Apple Watch can be interrupted when it is worn over tattoos.

Light sensors on the Watch, which went on sale last Friday (April 24), can be fooled by darker coloured artwork and even changes in dark skin colours, according to the manufacturer.

The heart rate sensor on the smart watch uses technology known as photoplethysmography to detect the amount of blood flowing through a users wrist by reflecting light off the skin.

According to a post on Apple’s website, numerous factors can affect the Watch’s ability to detect a heart beat, including temperature, motion and changes to skin colour, such as tattoos.

“Permanent or temporary changes to your skin, such as some tattoos, can also impact heart rate sensor performance,” the post explains. “The ink, pattern, and saturation of some tattoos can block light from the sensor, making it difficult to get reliable readings.”